PSI - Issue 71

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 71 (2025) 333–339

5 th International Structural Integrity Conference & Exhibition (SICE 2024) Static Strength Evaluation of Composite Aircraft Wing for One-Wheel Landing Case M. Mohan Kumar a* , Kumari Asha b , Lohith N b ,Byji Varughese b , Surendra C a , C. M. Manjunatha a

a Structural Integrity Division, CSIR-National Aerospace Laboratories, Bengaluru, India. b Advanced Composites Division, CSIR-National Aerospace Laboratories, Bengaluru, India.

Abstract Composite materials have been extensively employed in aircraft due to their high specific strength compared to traditional isotropic materials. In this study, the wing of a two-seater trainer aircraft, constructed using the Just-in-time Pre-preg (JIPREG) fabrication process, has been designed and developed for static strength evaluation. The wing structure includes skins, a primary load-bearing spar, two shear attachment spars, and transverse ribs. The skins, spar webs, and ribs are constructed using a sandwich design, featuring foam cores and glass bi-directional fiber composites as face sheet materials. As part of a weight optimization effort, the thicknesses of various wing components were optimized based on strength and stiffness criteria. The optimized design was then assessed through finite element analysis (FEA) using MSC NASTRAN, focusing on a critical one-wheel landing load case to estimate strains and deflections — an essential scenario for evaluating the main landing gear fittings. Subsequent to the FEA, a full-scale static strength test was conducted on the wing to meet the Joint Aviation Requirements Very Light Aircraft (JAR VLA) standards. The FEA results, including strain and deflection responses, were compared with the test outcomes under vertical and drag limit loads applied at all four landing gear attachment brackets. This work provides a detailed examination of the FEA predictions and various aspects of the full-scale static strength testing, including the design of the test rig, data monitoring via strain gauges, deflection gauges, and load cells. The testing results showed a strong correlation with the FEA predictions, confirming the safety of the landing gear attachments under the one-wheel landing scenario. The wing's bending strength was sufficient to support the limit loads without experiencing detrimental or permanent deformation in compliance with JAR VLA regulations. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SICE 2024 organizers

* Corresponding author, Email ID: mmk@nal.res.in. Phone: +91-(0)80-2508 6325 1. Introduction Keywords: Composite wing; FE analysis; Static strength; Landing loads; Strains; Deflections

Aircraft structure validation is a crucial step in the design process to ensure that the structure performs as intended in all aspects. The validation and certification process is primarily analytical, supported by test evidence from ultimate load tests or component-level limit tests. Static strength tests are necessary to verify the accuracy of internal loads and design allowances. The increasing use of composite materials in aviation has introduced challenges in designing and manufacturing lightweight, high-strength composite structures. Zhang W et al. developed a lightweight structure for a small, ultra-light solar UAV, with its structural integrity confirmed through finite element analysis and static testing. Du Chunzhi et al. employed geometric modelling and layering techniques to construct the composite wing of a low speed aircraft. The strength and stiffness of the wing, analyzed using ANSYS finite element software under various stacking configurations, showed that the composite wing provided superior stiffness, strength, and weight performance

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SICE 2024 organizers 10.1016/j.prostr.2025.08.045